GrahamH's photos with the keyword: measurements

A two page test report for the transmission links for a two-way radio system. The links joined the track-side base stations and the control centre. The system is no longer in use. This is used for checking the links shown here: www.ipernity.com/doc/grahamh/24117033

A two page test report for the transmission links for a two-way radio system. The links joined the track-side base stations and the control centre. The system is no longer in use. This is used for checking the links shown here: www.ipernity.com/doc/grahamh/24117033 E&M signalling over copper pairs in Australia was done using the 4W (1 pair each direction for the audio signal) circuit, ie no additional conductors. This is done in a similar manner to that used in feeding DC power to a condenser/electret microphone in a public address or studio sound system. The direct current for the signalling flows one way equally on both wires of a pair with the earth being used as the return conductor.

Equipment label, used to identify test gear for demonstrating that new telecommunication cables between telephone exchanges work correctly. Also used in complex fault finding. Work I did in the 70s.